Hybrid Wireless-optical Broadband Access Research Articles

An optimization framework for FiWi access network: Comprehensive solution for green and survivable deployment

Abstract Fiber Wireless (FiWi) access network also known as hybrid wireless optical broadband access network is a promising modern access technology as it provides high bandwidth, better flexibility, reliability and stability at lower cost. Likewise other access networks, energy saving and survivability are the most important issues in FiWi also. Therefore this paper provides an optimization framework as a comprehensive solution for deployment of green and survivable FiWi network. We optimize ONUs position in the network using different optimization algorithms such as genetic algorithm, teaching learning based optimization algorithm and whale optimization algorithm (Encircling Prey and Spiral Update Positioning). This optimization helps in achieving energy efficiency and survivability by mutually connecting maximum possible ONUs and wireless routers to each other. An extensive simulation is carried out to show the effectiveness of the present work. Simulation results show reduction in number of all time active ONUs, total physical distance among ONUs and associated wireless routers and total active time of the network. At the same time survivability is achieved by increasing average ONU connectivity of wireless routers. A detailed comparison of applied algorithms states that out of different optimization algorithms, genetic algorithm provides best energy efficiency but average survivability. Teaching learning based optimization & whale optimization algorithm (Encircling Prey) are average energy efficient but survivability offered by these algorithms are average and excellent respectively. Similarly whale optimization algorithm (Spiral Update Positioning) provides good energy efficiency but average survivability. Hence as per the need of energy efficiency and survivability, suitable optimization algorithm can be selected for deployment of green and survivable FiWi access network.

Wavelength-agile and radio-agile FiWi access network using dynamic scheduling to improve upstream delay and resource utilization

Fiber wireless (FiWi) access network which is also referred as hybrid wireless optical broadband access network is one of the modern architecture to solve the problem of bandwidth availability and flexibility simultaneously. It integrates wireless frontend with optical backend. In FiWi network most of component remains idle for large duration, hence efficiency is very crucial. To improve energy efficiency in FiWi many multiple access (MA) techniques had been implemented at backend. However inclusion of multiple access techniques usually incur problem of delay, as data transfer in such network takes place only in the assigned slot of access technique. In this paper a novel architecture is proposed for FiWi which implements wavelength agile hybrid multiple access at backend and radio agile access technique at frontend. Further to improve delay performance, bandwidth availability and utilization of resources; a new scheduling approach is proposed for multiple access techniques implemented at frontend as well as backend. Delay performance, wavelength availability and load handling capacity of proposed approach is compared with different hybrid multiple access architecture. To best of our knowledge, wavelength agile and radio agile MA has been used for the first time in FiWi, moreover the proposed scheduling approach implemented on MA provide promising results in terms of delay and resource utilization. The performance of proposed work is also evaluated in terms of service and reservation delay component to indicate its utility in terms of actual information content per frame. The result shows effectiveness of proposed architecture over other existing architectures.

Delay sensitive routing algorithm

Hybrid Wireless Optical Broadband Access Networks (WOBAN) are the cost effective solution to overcome the increasing demand of the bandwidth. However, there is significant mismatch in the performance of the wireless and optical part. In the wireless part of WOBAN, a packet has to travel through several hops due to which the data packet has to incur a significant delay. In this paper we propose a Delay Sensitive Routing Algorithm (DSRA) which significantly reduces the delay in the wireless part. The proposed DSRA treats the data on the basis of delay sensitivity. Simulation results show a significant improvement in the overall performance of WOBAN.

Performance evaluation of the survivability schemes in WOBAN: a quality of recovery (QoR) method

SummaryThe hybrid wireless optical broadband access network (WOBAN) is a combination of an optical backhaul and a wireless front‐end, which combine the huge amount of available bandwidth of optical networks and the ubiquity and mobility of wireless access networks with the objective of reducing their cost and complexity. Survivability is one of the most important issues in WOBAN. In this paper, the survivability schemes in WOBAN are addressed from a particular point of view of the quality of recovery (QoR) method. The QoR is a comprehensive measure to evaluate the survivability schemes in terms of availability, recovery time, redundancy, and bandwidth of backup path. The specific procedures to set up the analytical models for the survivability schemes in WOBAN are given based on the QoR concept, including abstract, normalization, and application. Besides, the weights assignment is provided to calculate the QoR value for the operators, home users, or business users with different requirements, which in turn offers the user‐perceptive quality of service. To verify the performance of the survivability schemes by the QoR method, extensive simulations are made under different WOBAN configurations. Numerical results show that for the intra‐domain survivability schemes, the wireless and optical mixed protection scheme is the best choice for failure recovery in WOBAN. The wireless scheme is the second choice for the solution, which emphasizes cost control, while for the solution that emphasizes the network performance, the 1:1 scheme is the second choice. The 1:N scheme obtains the worst QoR value as the splitter ratios increase. For the inter‐domain survivability schemes, optimizing backup optical networking units selection and backup fibers deployment scheme outperforms maximum protection with minimum cost scheme from the point of view of QoR. Copyright © 2013 John Wiley & Sons, Ltd.

Spectral efficient hybrid wireless optical broadband access network (WOBAN) based on transmission of wireless MIMO OFDM signals over WDM PON

In this paper, a spectral efficient hybrid wireless optical broadband access network (WOBAN) is proposed and demonstrated based on the transmission of wireless multi-input multi-output orthogonal frequency division multiplexing (MIMO OFDM) signals over wavelength division multiplexing passive optical network (WDM PON). By using radio over fiber (ROF) techniques, the optical fiber is well adapted to propagate multiple wireless services having different carrier frequencies. It is a known fact that multiple wireless signals having the same carrier frequency cannot propagate over a single optical fiber at the same time, such as MIMO signals feeding multiple antennas in fiber wireless (FiWi) system. A novel optical single-sideband frequency translation technique is designed and simulated to solve this problem. This technique allows four pairs of wireless MIMO OFDM signals with the same carrier frequency for each pair to be transmitted over a single optical fiber by using one optical source per wavelength. The crosstalk between the different MIMO channels with the same frequency is eliminated, since each channel is upconverted on specified wavelength with enough channel spacing between them. Also the maximum crosstalk level between the different MIMO channels with different frequencies is very low around −76dB. The physical layer performance of the proposed WOBAN is analyzed in terms of the bit error rate (BER), error vector magnitude (EVM), and signal-to-noise ratio (SNR). The proposed WOBAN achieves 7.68Gb/s data rate for 20km for the optical back-end and 240Mb/s for the outdoor wireless front-end.

Topology optimization for hybrid optical/wireless access networks

Hybrid Wireless–Optical Broadband Access Networks (WOBANs) are gauging momentum as flexible, bandwidth-effective, and cost-effective solutions for providing connectivity to residential users in metropolitan areas. In this work, we address the issue of designing the topology of deployed WOBANs. Namely, we consider the case where the coverage of a Ethernet-based Passive Optical Network (EPON) is extended by an additional wireless segment which features multi-hop wireless links operated either according to the IEEE 802.11 standard, or to the IEEE 802.16 one. We propose a mathematical programming model which optimizes the overall WOBAN topology in terms of deployment cost, while accounting for the specific traffic requirements of the residential users, and the specific features of the technological components. The potentials of the proposed model are showcased by deriving and commenting numerical results obtained when planning realistic WOBAN scenarios.